I bought some muscovy eggs from ebay, but these two ducks were hatched in 28 days. One is yellow, and one is gray. They grow very fast. They are only 10 days old now, but nealry 3 times biger than the 4 days onld muscovy ducks I bought. I asked the ebay seller what breed they were? She told me they were runner. While runner is usually smaller than Muscovy, so I doubt they might be other breeds. I even guess they might be a small breed of geese, because they are huge compared to other ducks. If any one can see their breed through the pictures, please let me know. Thank you. The small duckling is 4 days old Muscovy, which I bought from the farm. The gray duckling hatched in 28days too. She is smaller than the yellow big duckling, but she is still huge. The two black and yellow ducklings beside the big one are hatched in 32 days. I guess they are muscovy cross. If you can see their breed, please tell me too.